Door lock with alarm device



g- 1951 H. H. KEMPF DOOR LOCK WITH ALARM DEVICE 2 Sheets-Sheet 1 FiledNov. 29, 1949 I 'INVENTOR. flfFM/I/V fi Aim/PF ATTO/Q/VEV 7, 1951 H. H.KEMPF 2,563,727

DOOR LOCK WITH ALARM DEVICE Filed Nov. 29, 1949 2 Sheets-Sheet 2 I N VEN TOR. fife/14A /v ,6. Ai /w;

Patented Aug. 7, 1951 UNITED STATES PATENT OFFICE noon LOCK WITH ALARMDEVICE Herman H. Kempf, Garden City, N. Y., assignor to Abe April FineFurs, Incorporated, New York, N. Y., a corporation of New YorkApplication November 29, 1949, Serial No. 129,971

8 Claims. 1

Doors with spring extended latches are frequently opened by burglars byinserting a tool between the door and the frame to push back the latchbolt.

I propose to provide such latch mechanism with an alarm device whichwill attract attention in case the latch bolt is retracted byunauthorized action of the bolt but in which the door can be opened bymanual retraction of the bolt by a knob or finger lever in the propermanner or by a proper key without actuating the alarm.

One object is to provide a simple construction which is applicable to aconventional type of lock.

Accordingly I have provided alarm mechanism which can be combined with adoor lock to sound an audible alarm mechanically.

In carrying out the invention, I provide a push button type of alarmbell which is actuated when the latch bolt is pushed in by a toolinserted from outside the door. Retraction of the bolt by a knob orfinger lever at the inside of the door however disconnects the alarmdevice. Insertion of a proper key from outside the door also disablesthe alarm.

Fig. l is a front view of a lock and alarm device embodying one form ofmy invention showing it as mounted on the inside of a fragment of adoor.

Fig. 2 is a vertical sectional view of the same, the section being takenon the general plane of the line 2-2 of Fig. 1.

Fig. 2a is a rear view of the supporting plate for the cylinder lock ofFig. 2.

Fig. 3 is a rear view of the device, the. back plate of the lock unitbeing broken away.

Fig. 4 is a fragmentary horizontal section of a lock device, the sectionbeing taken on the plane of the line 4-4of Fig. 3,

Fig. 5 is an enlarged perspective view of parts of the bolt retractingmechanism and the cam for initiating an alarm.

Fig. 6 is an enlarged perspective view of a part shown in Fig. 5, theview being taken at a different angle.

The lock case or housing 8 is adapted to be attached by screws 9 to adoor I and supports the spring-pressed latch bolt I l which is adaptedto be retracted manually by a lever [2 or a key l4. The back plate l ofthe case is secured in place by a screw IS.

The latch bolt is slidably guided in one end of the case and has tworods ll, H which are slidable in a saddle l8 which is supported in theguide IS in the case. The springs 29, 20 on these 2 rods bias the boltto a protruded latching position.

At the inner ends of the rods ll are abutment plates 2| and 22. Fingerlever l2 extends through a slot in the case and is pivoted at 22' toplate 22. The arm 23 is hinged on stud 24 which is secured in plate 2|.This arm extends through a slot in the case and carries at its upper endan inclined cam 25 which coacts with a spring-pressed button 26 of aspring-driven alarm bell 21 which may be suitably mounted on or may beadjacent the lock case. A leaf spring 28 is secured at one end to arm 23and presses at the other end against the wall of the case to press theupper end of arm 23 and its cam 25 toward the rear of the case where thecamis in alinement with the alarm button 26.

The rear of arm 23 has a shoulder 29 which is engaged by a hook..3ll onthe inner end of finger lever l2 so that when the finger piece is movedto the right (Fig. 1) or left in Fig. 3, the upper end of arm 23 and cam25 will be moved forward and out of alinement with the alarm button.Continued movement of the lever retracts the entire bolt unit withoutmoving the alarm button.

If the bolt and its unit are pushed inward, the cam 25 engages the alarmbutton and releases the alarm.

To retract the latch bolt from the outside of the door, I provide acylinder type lock having a roll back 3| which is rotatably carried bythe back plate l5 and has arms which engage the abutment plates 2| and22. The cylinder body 32 has the pin carrying plug 33. The support 34 issecured to the door by screws or brads 35. The cylinder 32 is secured byscrews 35, 36 to support 34. The rear ring 31 is secured to the pin plug33 by screws 38, 38. A blade 39 has an enlarged end 48 slidably mountedin the inner end of the key slot of the pin plug 33. The blade 39extends through a slot in ring 3! and through the central slot in theroll back 3| so that the bolt unit can be retracted by rotation of a keyin the cylinder lock. When a key of ordinary length is inserted into thelock cylinder, the associated alarm parts are not disturbed and remainset so that rotation of the key will retract the bolt and sound thealarm. However, insertion of a special key of extra length will engagethe end 43 of the blade 39 and push the blade against the arm 23 andtilt the arm thereby retracting the cam 25 from alinement with the alarmbutton 26 so that subsequent rotation of the key will retract the boltto open the lock Without sounding the alarm.

The lock may be provided with a dead lock catch 4| so that afterretracting the bolt by means of the lever 12 the bolt may be heldretracted without sounding the alarm.

I claim:

1. In an alarm system, the combination of a door lock. casing containinga latching unit therein and having a spring-pressed slidable latch boltmember for locking the door and adapted to be slidably retracted intothe casing, to unlocking position an alarm device including an actuatingbutton, an alarm initiating member movably carried by said latching unitand adapted to coact with said button to initiate an alarm when the boltis pushed into the casing, to unlocking position and manually operablemeans for retracting said bolt latching unit and retracting said alarminitiating member from coaction with said actuating button.

2. In an alarm system, the combination of a door lock casing containinga latching unit therein and having a spring-pressed slidable latch boltmember for locking the door and adapted to-be slidably retractedinto thecasing to unlocking position, an alarm device including an actuatingbutton, an alarm initiating cam member hinged to said latching unit andadapted to coact with said button to initiate an alarm when the bolt ispushed into the casing, and a finger actuated lever for retracting saidbolt latching unit and retracting said alarm initiating cam member fromenacting with said actuating button.

3.. A. door lock Witha casing and a normally protruding spring-pressed.sliding bolt unit for attachment to the inside of a door in combination.with a push button-actuated alarm device actuator, a cam movablyconnected to the bolt unit and slidable with the bolt unit to engage thepush button actuator and initiate an alarm when the bolt is forcedinwardly of the casing by an outside force, a manually operable leverconnected to said cam at the inside of the door for disengaging said camfrom said push button actuator when retracting said bolt unit from theinside, and means actuated by a key from outside the door for retractingsaid bolt unit.

4. A door lock with a casing and a springpressed sliding bolt unit innormal protruding locking position for attachment to the inside of a.door in combination with a push buttonactuated alarm device actuator, acam movably connected to the bolt unit and slidable with the bolt unitto engage the push-button actuator and. initiate an alarm when the boltis forced to unlocked position by a force outside the door, a manuallyoperable lever connected to said cam at the inside of the door fordisengaging said cam from said push button actuator when retracting saidbolt unit from the inside, and means actuated by a key from outside thedoor for re tracting said cam and retracting said bolt unit.

5. A door lock for use with an alarm device comprising a lock casing, abolt unit slidably mounted in said casing and having one end of the boltprotruding externally therefrom, a cam member connected to the bolt unitand normally projecting'ex-ternally of the casing for engagement with aprojecting actuating part of an alarm device and adapted to slide innormal alarm releasing position when the bolt unit is moved by forcingthe bolt longitudinally at its protruding end, and key actuated meansfor simultaneously retracting said bolt and retracting said cam fromalarm releasing position.

6. A door lock with alarm attachment comprising a lock casing containinga latch bolt unit including means slidable in the casing, an alarmdevice including a projecting element for initiating action of the alarmdevice, means carried by the latch bolt for coacting with saidprojection to cause an alarm when said latch bolt is pushed into saidcasing, and manually operable means including a finger piece forretracting said latch bolt unit and simultaneously deflecting said boltcarried means from said projection and preventing it from coacting withsaid projection when said latch bolt unit is'retracted by said fingerpiece.

7. A door lock with alarm attachment comprising a lock casingcontainingalatching unit including a bolt and a roll back for retractingsaid bolt and having key actuated means at one face and manuallyactuated means at the opposite face, each of said means coacting withsaid roll back to retract said bolt, an alarm device having an operatingbutton, a cam carried by said latching unit and slidable with said bolt,when the bolt is pushed in, for engaging said operating button toinitiate the alarm action, and means adapted to be actuated either bythe key actuating means or by said manually actuated means for disablingsaid cam and avoiding said alarm.

8. An alarm system comprising, in combination, a bell device having aprotruding actuating member, and door locking mechanism including a lockcasing, a spring-pressed locking bolt unit slidable therein and having abolt normally protrudingfrom said casing in looking position, a hingedcam device in said casing and having a portion protruding from saidcasing and movable in the path of said actuating member, and means ofconnection between said cam device and said locking unitv wherebymovement of the bolt locking unit by a force externally of the easing onthe protruding bolt will carry the cam device along and move theprotruding portion thereof over said actuating member for ringing thebell, said connecting means including plates carried by the sliding boltand a stud carried by one of the plates for hingedly connecting the camdevice to the locking unit.

HERMAN H. KEMPF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 531,955 Larson Jan. 1, 1895583,952 Sutton June 8-, 18-97 FOREIGN PATENTS Number Country Date 2,963Great Britain Dec. 8', 1910

